Patch antennas in common use today are typically constructed of three flat, conductive layers in superpose alignment. The first layer typically has a plurality of spaced, conductive, rectangular patches formed on a surface. The second layer is typically a solid conductive layer with a cut-out slot that underlying each rectangular patch of the first layer. The third layer has an arrangement of conductive feed traces which underlie the cut-outs in the second layer.
Conventional patch antennas are constructed by forming the slot (second) and feed (third) layers on a conventional, two-layered printed circuit board. The first layer, with the rectangular metallic sections, is then positioned at a distance above the circuit board through the use of mechanical standoffs, or the like. The expense of the printed circuit board, the patch assembly with the rectangular sections, and the standoffs makes the patch antenna a relatively high cost item.
It is an object of the present invention to provide a patch antenna structure which is relatively inexpensive, yet is able to maintain the accuracy required in the positioning of the components of each of the layers of the antenna and the relative positioning of the layers.